1. Field of the Invention
The present invention relates generally to contactless smart cards and validator devices for communicating data with them and, more specifically, to validator devices used on board transit vehicles.
2. Description of the Related Art
Credit card-sized devices having memory, processing logic or other digital and analog electronics are commonly known as smart cards. Certain types of smart cards, commonly known as contactless smart cards, can communicate data with a validator device via a wireless radio frequency (RF), inductive or similar communication link that does not require electrical (galvanic) contact between the smart card and validator device. Smart farecards have been used for, among other purposes, payment of mass-transit fares. A patron can purchase a farecard having a certain denomination or value that corresponds to an account balance. To board a mass-transit vehicle, the patron places the farecard in the vicinity of the validator device. Via wireless or otherwise contactless communication between the validator and farecard, the validator device detects the presence of the farecard, identifies the account associated with that farecard, and debits the account balance. If the account balance is greater than the fare, the validator indicates such and allows the patron to board the vehicle. The transaction may include other steps as well, such as confirming the authenticity of the farecard. In some mass-transit systems, patrons must also present their farecards to the validator device upon exiting the vehicle. Such systems are sometimes referred to as check-in check-out (CICO) systems because a patron must use the validator both upon entering or checking into the vehicle and exiting or checking out of the vehicle. A CICO system can base the fare upon distance traveled, travel zones crossed or time elapsed.
Prior contactless CICO validator devices suffer from a number of problems. One problem is unintended check-out. Such a validator device is typically mounted at a height conveniently within the reach of a patron of average height. The device typically includes an antenna of a type and oriented in a manner that result in projection of an electromagnetic field in a generally horizontal direction. As a patron moves closer to the device the field thus becomes more intense. If a patron who has checked in stands too near the validator device during the ride, communication may occur between the validator device and a farecard in his shirt pocket, resulting in an unintended check-out transaction.
Another problem is that the RF field emanating from the validator device points directly at the patron. Although medical research has been inconclusive, it has been suggested that the cumulative effects of even very low energy RF fields can be harmful to persons, particularly those who have cardiac pacemakers.
Another problem is that a patron may withdraw the farecard before a check-in or check-out transaction has been completed. A typical smart card transaction takes between 100 and 300 milliseconds to complete. A patron may not appreciate how near the validator device he must bring the card and how long he must allow the card to remain there. An unknowledgeable patron may attempt to quickly wave the card by the validator device. Although a display or similar indicator on the validator device may alert the patron that the transaction did not complete, a patron may not deduce from such an indication that he should move the card more slowly or bring it closer to the device.
It would be desirable to provide a smart card validator device that inhibits unintended transactions with smart cards near the device, that promotes proper placement of a card when a transaction is intended, and that minimizes potential health risks from exposure to stray RF fields. These problems and deficiencies are clearly felt in the art and are solved by the present invention in the manner described below.